Examine source code of HollowKnightSS

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "HollowKnightSS",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(32, 32, 32)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(200, 200, 200)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(35, 205, 154)",
      "popup": "rgb(32, 32, 32)",
      "popup_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(35, 205, 154)",
      "tab_selected": "rgba(35, 205, 154, 0.29)",
      "toolbar_bottom_separator": "rgb(35, 205, 154)",
      "toolbar_field_border_focus": "rgb(35, 205, 154)",
      "toolbar_field_separator": "rgb(35, 205, 154)",
      "toolbar_vertical_separator": "rgb(35, 205, 154)",
      "tab_loading": "rgb(35, 205, 154)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d9ee1fd2-8372-4da4-829b-0e903d03006d}"
    }
  }
}